Data deduplication eliminates redundant data to improve storage utilization and reduce the amount of data sent over a network. Deduplication reduces the required storage capacity and network bandwidth because only one copy of a unique data unit is stored and/or sent. Disk based storage systems, such as a storage management server and Volume Tape Library (VTL), may implement deduplication technology to detect redundant data and reduce duplication by avoiding redundant transfer and/or storage of such data.